if 5>2:
    print("5大于2")
    print("22222")
else:
    print("5小于2")

if 5>12:
    print("5大于12")
    print("1212121212")
else:
    print("5小于12")

age=30
if age<18:
    print("You are underaged")
elif age>=18 and age<30:
    print("You are young")
elif age>=30 and age<50:
    print("You are middle-aged")
else:
    print("You are old")

print("===============================")

# #判断闰年
# year = int(input("请输入年份:"))
# if (year%4==0 and year%100!=0) or (year%400==0):
#     print("%d是闰年"%year)
# else:
#     print("%d不是闰年"%year)
#
# #a b c比较大小
# a=int(input("请输入a:"))
# b=int(input("请输入b:"))
# c=int(input("请输入c:"))
# if a>b:
#     if a>c:
#         print("a is the largest")
#     else:
#         print("c is the largest")
# else:
#     if b>c:
#         print("b is the largest")
#     else:
#         print("c is the largest")

#计算器实现加减乘除
num1 = float(input("请输入第一个数字:"))
num2 = float(input("请输入第二个数字:"))
op = input("请输入运算符:")
if op=="+":
    print(num1+num2)
elif op=="-":
    print(num1-num2)
elif op=="*":
    print(num1*num2)
elif op=="/":
    print(num1/num2)
else:
    print("输入错误")